This invention relates to a nonexplosive chemical composition for gently and noiselessly breaking a rock or concrete mass.
Explosives have widely been used in the field of civil engineering for breaking or cracking rocks or constructions of concrete and also for demolition of old buildings, and in some cases mechanical means have been employed instead of explosives to apply shocks to the objectives of breaking or demolishing. However, the breaking or demolishing operations by these means are accompanied by loud noises, intense vibrations and scattering of debris, and even generation of harmful gases in the cases of using explosives. Therefore, troublesome countermeasures are taken for ensuring safety and preventing pollution, but, nevertheless, the traditional methods are unsuited to practice in densely populated or densely built-up areas.
With a view to gently and noiselessly breaking a rock or concrete mass it has been devised to utilize an expansion pressure developed upon hydration of quick lime or calcium oxide, and some kinds of nonexplosive chemical compositions using calcined quick lime as the principal material have been developed and industrialized to some extent. Rock or concrete breaking compositions of this type are used in the form of an aqueous slurry, which is poured into holes drilled in the objectives of breaking. As the hydration proceeds the slurry sets with development of an expansion pressure, whereby cracks extend from the periphery of each drill-hole to result in gradual breaking of the rock or concrete mass.
However, conventional compositions of the above described type are not yet satisfactory for some reasons such as insufficiency of the expansion pressure, great dependence of the hydrating property on the ambient temperature and/or relatively low density of calcined calcium oxide in the powdery composition.